1. Field of the Invention
The present invention relates to a transmission apparatus, more particularly relates to a transmission apparatus provided with a synchronous optical network/synchronous digital hierarchy (SONET/SDH), wavelength division multiplexing (WDM), or other interface
As such transmission apparatuses, in general, there are add-drop multiplexer (ADM) apparatuses, cross-connect apparatuses, optical ADM (OADM) apparatuses, optical cross-connect (OXC) apparatuses, etc. Further, in the present invention, the transmission apparatuses include transmission apparatuses for adding/dropping, cross-connecting, or switching plesiochronous digital hierarchy (PDH) signals, asynchronous transfer mode (ATM) signals, and Ethernet signals. Further, the present invention may also include all sorts of transmission apparatuses (communication apparatuses) for transmitting Internet protocol (IP) signals
2. Description of the Related Art
Conventional SONET/SDH transmission apparatuses manage networks, including ring switching at the time of occurrence of line faults, at only the SONET/SDH layers by monitoring, terminating, and adding overhead of SONET/SDH frames.
WDM transmission apparatuses also manage networks at only the WDM layers.
Further, IP transmission apparatuses manage networks only between routers switching the IP signals, that is, only between one router and another. In other words, they can only manage networks at the transmission control protocol/IP (TCP/IP) layers.
In recent years, in view of all of this, various integrated network management techniques have been proposed with the intention of integrally managing IP networks and optical networks. These integrated network management techniques will be explained in detail later with reference to the drawings.
As will become evident later, however, in the past, no technique has been proposed enabling entire networks to be integrally managed by having single transmission apparatuses perform processing for the SONET/SDH/WDM layers and the TCP/IP layers. In the final analysis, there has therefore been the problem that it has not been possible to greatly reduce the capital costs and running costs of an optical network for transmitting IP signals.